DELTA DVP SERVO INDEX — REVIEWABLE TEACHING PSEUDOCODE
Version: 2026-08-31
Purpose: state and evidence design for one pulse/direction indexing axis

IMPORTANT
This is not an ISPSoft, WPLSoft or DIADesigner import. It deliberately uses symbolic
roles instead of universal X/Y/M/D addresses. Map the exact CPU, firmware, output
channel, instruction variant, drive series, electrical interface, units and status
devices from the controlled Delta manuals. Validate safety functions independently.

TEACHING UNITS
Ball screw pitch              = 10 mm/revolution
Approved command resolution   = 20,000 command pulses/revolution
Pulses per mm                 = 20,000 / 10 = 2,000 pulses/mm
Relative move distance        = 50 mm
Relative move command         = 50 * 2,000 = 100,000 pulses
Target speed                  = 25 mm/s
Pulse frequency               = 25 * 2,000 = 50,000 pulses/s
Acceleration/deceleration     = 500 ms placeholder; engineer for the real load

SYMBOLIC INPUTS
AxisReady, AxisAlarm, AxisInPosition, AtZeroSpeed
HomeSensor, ForwardLimit, ReverseLimit
EnableRequest, HomeRequest, MoveRequest, ResetRequest
RequestedDistance_mm, RequestedSpeed_mm_s

SYMBOLIC OUTPUTS
ServoEnableCommand, AlarmResetPulse
PulseChannel, DirectionChannel

OBSERVABLE INTERNALS
State, FirstOutFault, Referenced
RequestAccepted, RequestRejected, RejectReason
CommandPulses, CommandFrequency, MoveInstructionActive
PulseOutputComplete, MoveTimeout, DonePulse

ACCEPTANCE CONDITION
CanAcceptMove :=
    State = IDLE
    AND Referenced
    AND AxisReady
    AND NOT AxisAlarm
    AND NOT ForwardLimit
    AND NOT ReverseLimit
    AND ParametersValid
    AND SafetyPermissionStatus;

REQUEST EDGE
On rising edge of MoveRequest:
    IF CanAcceptMove THEN
        latch RequestedDistance_mm and RequestedSpeed_mm_s;
        calculate pulses and frequency with checked wide arithmetic;
        range-check direction, travel target, pulse count and frequency;
        IF checks pass THEN RequestAccepted := TRUE; State := MOVING;
        ELSE RequestRejected := TRUE; RejectReason := RANGE_OR_MATH;
    ELSE
        RequestRejected := TRUE;
        RejectReason := first false acceptance condition;
    END_IF;

MOVING ENTRY
Call exactly one target-supported relative-position instruction such as the exact
DRVI/DDRVI variant documented for the selected CPU and paired transistor outputs.
Do not substitute the following symbols directly as an instruction signature:

    ExecuteRelativePulseMove(
        pulse_count := CommandPulses,
        pulse_frequency := CommandFrequency,
        pulse_channel := PulseChannel,
        direction_channel := DirectionChannel);

MOVING STATE
IF AxisAlarm THEN
    FirstOutFault := DRIVE_ALARM; State := FAULT;
ELSIF target-direction limit becomes active THEN
    FirstOutFault := TRAVEL_LIMIT; State := FAULT;
ELSIF MoveTimeout THEN
    FirstOutFault := MOVE_TIMEOUT; State := FAULT;
ELSIF PulseOutputComplete AND AxisInPosition THEN
    State := COMPLETE;
END_IF;

COMPLETE STATE
DonePulse := TRUE for one scan/event;
Record final commanded coordinate, drive status and independent measured position;
State := IDLE only after the request handshake is released/acknowledged.

FAULT / RECOVERY
Preserve FirstOutFault and drive alarm code before reset.
Do not use AlarmResetPulse until the cause is removed, motion is inhibited, the
axis is in the approved state and a new authorized ResetRequest edge occurs.
Reset must not create a move. Reference validity after a fault is a written decision,
not an assumption.

HOMING
Use the exact target-supported ZRN/homing method and verified sensor/limit polarity.
A robust sequence may search, detect DOG/origin, back off, re-approach slowly and
latch the approved coordinate. Block absolute moves until Referenced is true.

DONE IS NOT JUST "PULSES SENT"
PLC pulse output complete means the controller has finished generating a command.
Drive In Position means the drive reports that its position-error condition is within
its configured criterion. Production Done may require both, no alarm, valid reference,
stable status for an approved dwell and external process evidence.

TREND TOGETHER
MoveRequest, RequestAccepted, State, CommandPulses, CommandFrequency,
MoveInstructionActive, PulseOutputComplete, AxisReady, AxisAlarm, AxisInPosition,
HomeSensor, both limits, Referenced, CommandedPosition, ActualPosition, timeout and
FirstOutFault on one time base.